Question

a male cardinals red color is an example of a trait affected by natural selection. the females of the species choose mates based on the vibrant colors of the males feathers. if females begin using different criteria than feather color when they choose mates, what would most likely happen to the color of the male cardinals over time?
increased variation in the shades of red because there is no advantage in one specific color
increased variation in the shades of red because the cardinals try different ways to impress the females
decreased variation in the shades of red over time because no form of the trait is advantageous
decreased variation in the shades of red after a single generation

Explanation:

When female cardinals stop using male feather color as a mate-selection criterion, the vibrant red color no longer provides a reproductive advantage. Without natural selection favoring a specific shade of red, genetic variation in feather color will no longer be constrained. Random genetic changes and the lack of selection pressure will lead to more variation in red shades over time, as no single color helps males reproduce more successfully.

Answer:

increased variation in the shades of red because there is no advantage in one specific color